1. Field of the Invention
The present invention relates to a component built-in module, and a manufacturing method for the component built-in module, which are for having electronic components built-in using electric insulating sheet members, for example.
2. Related Art of the Invention
Recently, a demand for downsizing and weight reduction, and a high-function and high-performance of electronic equipment has been getting more and more intense, and the amount of data handled has been increasing dramatically.
Hence, high density mounting of electronic components is demanded of wiring substrates used for electronic equipment.
In order to mount electronic components in high density, development of three-dimensional mounting technology has been performed for, in wiring substrates, fabricating thin-film electronic components, or having semiconductors, capacitors and the like built-in, which are existing electronic components.
One example of such a three-dimensional mounting technology is a component built-in module having active components such as semiconductors and the like and passive components such as capacitors and the like embedded in electric insulating sheet members including inorganic filler and heat-hardening resin.
Since particulate-like inorganic filler is included in plenty, electronic components can be embedded easily in the component built-in module with high heat dissipation and low permittivity.
And, since short wiring is formed and shielding effect can also be produced, a component built-in module with high noise immunity is useful as a wiring substrate coping with high frequency operation such that three-dimensional mounting is performed in high density.
Meanwhile, as a method of obtaining conduction between upper and lower wiring patterns in the component built-in module, a method is known that forms via holes in sheet members, and forms via conductors by filling the said via holes with a conductive paste (see, for example, Japanese Patent Laid-Open No. Hei 11-220262).
Here, mainly with reference to FIGS. 9 to 13, such a conventional manufacturing method for a component built-in module is concretely described.
Further, FIG. 9(A) is a schematic vertical sectional view for describing the gluing of the protective films 102a and 102b related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 9(B) is a schematic vertical sectional view for describing the formation of the cavity 104 related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 9(C) is a schematic vertical sectional view for describing the gluing of the new protective film 102c related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 9(D) is a schematic vertical sectional view for describing the formation of the via hole 105 related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 9(E) is a schematic vertical sectional view for describing the filling up with the conductive paste 106 related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module, and FIG. 9(F) is a schematic vertical sectional view for describing the peel-off of the protective films 102b and 102c related to the formation of the sheet member 110 in which the cavity 104 is formed, in the formation step of the first conventional manufacturing method for the component built-in module.
Furthermore, FIG. 10(A) is a schematic vertical sectional view for describing the gluing of the protective films 102a and 102b related to the formation of the sheet member 120 in which the cavity 104 is not formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 10(B) is a schematic vertical sectional view for describing the formation of the via hole 105 related to the formation of the sheet member 120 in which the cavity 104 is not formed, in the formation step of the first conventional manufacturing method for the component built-in module, FIG. 10(C) is a schematic vertical sectional view for describing the filling up with the conductive paste 106 related to the formation of the sheet member 120 in which the cavity 104 is not formed, in the formation step of the first conventional manufacturing method for the component built-in module, and FIG. 10(D) is a schematic vertical sectional view for describing the peel-off of the protective films 102a and 102b related to the formation of the sheet member 120 in which the cavity 104 is not formed, in the formation step of the first conventional manufacturing method for the component built-in module.
Furthermore, FIG. 11(A) is a schematic vertical sectional view for describing a state before a heat press in the heat press step of the first conventional manufacturing method for the component built-in module, FIG. 11(B) is a schematic vertical sectional view for describing a state during a heat press in the heat press step of the first conventional manufacturing method for the component built-in module, and FIG. 11(C) is a schematic vertical sectional view for describing a state after a heat press in the heat press step of the first conventional manufacturing method for the component built-in module.
Furthermore, FIG. 12(A) is a schematic horizontal sectional view for describing a state during a heat press in the heat press step of the second conventional manufacturing method for the component built-in module, and FIG. 12(B) is a schematic horizontal sectional view for describing a state after a heat press in the heat press step of the second conventional manufacturing method for the component built-in module.
Furthermore, FIG. 13(A) is a schematic horizontal sectional view for describing a state during a heat press in the heat press step of the third conventional manufacturing method for the component built-in module, and FIG. 13(B) is a schematic horizontal sectional view for describing a state after a heat press in the heat press step of the third conventional manufacturing method for the component built-in module.
Here, a horizontal sectional view means a sectional view taken by cutting with a horizontal plane parallel to the sheet member, and a vertical sectional view means a sectional view taken by cutting with a vertical plane perpendicular to the said horizontal plane (the same shall apply hereinafter in this regard).
As shown in FIG. 9(A), a sheet member 103 with thickness of about 100 μm is formed by gluing protective films 102a and 102b onto both faces of an unhardened composite sheet 101.
As shown in FIG. 9(B), a cavity 104 according to the shape of a built-in electronic component 131 (see FIG. 11(A)) is formed in the sheet member 103 by any of laser processing, punch processing and drill processing.
As shown in FIG. 9(C), an opening of the cavity 104 is stopped up by gluing a new protective film 102c after peeling off the protective film 102a on one side.
As shown in FIG. 9(D), a via hole 105 penetrating the sheet member 103 is formed by any of laser processing, punch processing and drill processing.
As shown in FIG. 9(E), the via hole 105 is filled up with a conductive paste 106 using a means such as a printing process and the like.
As shown in FIG. 9(F), a sheet member 110 is completed by peeling off the protective films 102b and 102c. 
As shown in FIGS. 10(A) to 10(D), a sheet member 120 is prepared by a process that is, except that the cavity 104 is not formed, similar to the process of forming the sheet member 110 described above.
Here, the sheet member 120 fulfills the role of preventing the interference between the built-in electronic component 131 (see FIG. 11(A)) and a second wiring substrate 140 (see FIG. 11(A)).
As shown in FIG. 11(A), two sheet members 110 in which cavities 104 (see FIG. 9(B)) are provided; the sheet member 120; a first wiring substrate 130 including a first wiring pattern 132, and the electronic component 131 mounted on the first wiring pattern 132; and the second wiring substrate 140 including a second wiring pattern 141 are aligned.
As shown in FIG. 11(B), a heat press is performed against the two sheet members 110, the sheet member 120, the first wiring substrate 130, and the second wiring substrate 140, which are aligned and stacked up.
As shown in FIG. 11(C), the component built-in module is finally manufactured in which the first wiring pattern 132 and the second wiring pattern 141 are electrically connected by a via conductor 151 formed using the conductive paste 106 (see FIG. 9(E) and FIG. 10(C)).
In the conventional manufacturing method for the component built-in module like this, since, as shown in FIG. 11(B), there is a gap 133 between the electronic component 131 and a wall surface of the cavity 104, a via flow is often generated that is a phenomenon in which the resin forming the sheet members 110 and 120 flows due to heating and pressurization through a heat press.
Consequently, the via conductor 151 is deformed due to the via flow, and an electrical connection defect sometimes occurs.
Meanwhile, a method is known that forms beforehand a sub space for internal volume adjustment in a sheet member, in order to suppress such a via flow (see, for example, Japanese Patent Laid-Open No. 2004-319701).
Here, mainly with reference to FIGS. 14 and 15, such a conventional manufacturing method for a component built-in module is concretely described.
Further, FIG. 14 is a schematic vertical sectional view for describing a state before a heat press in the heat press step of the fourth conventional manufacturing method for the component built-in module.
Furthermore, FIG. 15(A) is a schematic horizontal sectional view for describing a state during a heat press in the heat press step of the fourth conventional manufacturing method for the component built-in module, and FIG. 15(B) is a schematic horizontal sectional view for describing a state after a heat press in the heat press step of the fourth conventional manufacturing method for the component built-in module.
As shown in FIG. 14, in the conventional manufacturing method for the component built-in module like this, a via hole 502 filled up with a conductive paste is formed in a sheet member 501, an electronic component 504 is arranged in a cavity 503, and a sub space 505 is formed.
The said component built-in module comprises a via conductor 506 formed using the conductive paste with which the via hole 502 is filled up, the electronic component 504, and the sub space 505 filled up at least with resin.
The volume of the sub space 505 is approximately the same as the volume of a gap between the electronic component 504 and a wall surface of the cavity 503, and a via flow is suppressed.